A hydraulic composition is essential as materials for constructing civil works and architecture and, for example, cement compositions such as cement paste, mortar and concrete are widely used. In such the field of civil works and architecture, a cement composition and the like having high fluidity and not causing the segregation of materials is required in order to enhance the working efficiency. For this purpose, a water reducing agent having an effect of improving the strength and the durability of curing product by enhancing the fluidity of cement composition and reducing its water content, and a material segregation reducing agent providing resistance to material segregation by an effect of enhancing the viscosity of the cement composition are added. For example, naphthalene based or polycarboxylic acid based water reducing agents, or polymers such as cellulose and glucan as a material segregation reducing agent (thickener) are added.
Japanese Kokai Publication 2001-48619 (p. 2-3) discloses that with respect to a material segregation reducing agent for cement compositions, when pyrrolidone-sodium acrylate copolymer is used as a material segregation reducing agent, a cement composition having high fluidity and not causing the segregation of materials is attained and a material segregation reducing agent is used in a very small amount. However, in such cement composition to which a material segregation reducing agent is added, there was room for contrivance to enhance its setting rate and to further enhance the working efficiency in the construction field of civil works and architecture and the like.
Japanese Kokai Publications Hei-6-263506 (p. 1-2, 3-4) discloses a hydraulic composition containing a binder including coarse cement, β-1,3-glucan, and a high-performance water reducing agent. However, in this hydraulic composition, an amount of addition of β-1,3-glucan based on the cement is large and characteristics such as high fluidity and material separation reducing cannot be efficiently attained. Therefore there was room for contrivance to improve this point and to make the composition excellent in the working efficiency in the construction field of civil works and architecture and the like.